In general, two variants are known in response to a lamp being extinguished as a result of an interruption to the voltage supply: in the first variant, the lamp is restarted without preheating, which could, however, result in a cold start. A cold start entails an increased work function of the electrons on the electrodes, which leads to premature wear of the filament electrodes. One advantage of this, however, is the fact that the lamp emits light again within a very short period of time. This procedure is therefore preferred, for example, when switching over to an emergency power supply. In the second variant, there is preheating again in any case, which leads to an additional dark phase of up to two seconds, depending on the lamp type, but 100% guarantees switching strength. A procedure known from the prior art which is improved compared to these two variants uses a timing element in order to establish the duration of the system interruption and to decide whether preheating is required again or not. This may lead to useful results in the case of circuit arrangements which have been constructed for a specific lamp type. Recently, however, so-called multilamp electronic ballasts (multilamp EBs) have been used more and more which can operate different types of lamp, i.e. in particular lamps with different types of filament. Owing to the different physical properties of the different types of filament, the procedure with determination of the time duration of the system interruption can therefore only be a compromise.